Portable fastener driving device

ABSTRACT

The present invention includes various embodiments directed to apparatus and methods surrounding a fastener device. In particular embodiments, the fastener device is a quick charging and discharging device that includes a solenoid, a fastener striker, a flash capacitor, and a control circuit. Other novel features of the fastener device exist. In particular embodiments, the present invention also includes apparatus and methods related to deforming staples for securing conduit and the like, and staple insulation and insulated staples that may be discharged by the fastener device. The insulation may be provided in an ordinary staple strip for use in the fastener device. Each insulation form may include deformation voids to assist the adaptation of the insulation about a target object that is being secured by the insulated staple.

This application is a continuation of U.S. application Ser. No.11/944,607, and therefore claims priority to U.S. application Ser. No.11/944,607, filed Nov. 24, 2007, now pending, which claims priority toU.S. provisional patent application Ser. No. 60/887,091, filed Jan. 29,2007, the disclosure of each being hereby incorporated by reference.

DESCRIPTION OF THE RELATED ART

Embodiments of the present invention relate to a device for drivingstaples and other fasteners. More specifically, embodiments of thepresent invention relate to a portable, lightweight, hand-held devicethat utilizes a DC source to effectively drive staples or otherfasteners under heavy duty applications at elevated drive forces and atshort intervals of time while maintaining an extended battery life.

Prior art staplers and other fastener driving devices are well known.Many of these devices are manual (i.e., spring driven) or solely utilizean alternating current (AC) power source. Other fastener driving devicesutilize direct current (DC) sources, such as batteries. DC drivendevices are appealing for their portability; however, there are severaldraw-backs that significantly reduce their commercial appeal for heavyduty industrial or commercial uses.

Industrial or commercial fastener driving devices must be reliable,quickly refire, and drive the desired fasteners consistently andsecurely into more resistant (i.e., harder or denser) materials, suchas, for example, wood, plastics, concrete, and composites thereof.Because batteries contain a limited amount of stored energy, it isdifficult to provide high driving power while still providing quickrefiring capabilities and an extended battery life. Consequently, priorart solenoid-driven fastener driving devices do not consistently provideelevated driving power with quick firing and recharging (i.e., refiring)capabilities. Further, DC operated devices may have severely limitedbattery life.

Staples are often used to secure cable and the like in homes andcommercial buildings. To prevent cables and the like from moving, it maybe desirous to deform a staple about the cable. Further, insulatedstaples are becoming more and more desired because they provide aflexible interface between the staple and the cable. This flexibleinterface is more forgiving and, therefore, safer since it is less aptto cut or abrade the cable, such as when the staple is over driven, whenthe cable moves due to ambient temperature fluctuations or cableexpansion from electrical heat generation within the cable, or byrelative movement between the cable and structure. Presently, therelacks an efficient means of manufacturing and providing an insulatedstaple, and providing insulation that is capable of properly shearingfrom a clip and adapting to a rounded cable or the like.

Accordingly, there remains a need to provide a fastener driving deviceand insulated staples that meet the inadequacies and deficiencies in theprior art, including those identified above. The fastener driving deviceand staples disclosed herein provide novel solutions to these and otherproblems.

SUMMARY OF THE INVENTION

Particular embodiments of the present invention include an apparatus fordischarging and driving fasteners into work pieces. Particularembodiments of the present invention include a nailer or stapler devicethat includes a solenoid and a fastener striker in operationalcommunication with the solenoid. The device also includes a flashcapacitor in operational communication with the solenoid, the capacitoroperating at 400 or more microfarads and having a charging capacity ofat least 180 volts. The device further includes a control circuit inoperational communication with the flash capacitor, the circuitconfigured to fully charge the flash capacitor from a direct currentpower source and fully discharge the capacitor within approximately 20seconds or less, the power source having a charging capacity of at leastapproximately 12 volts.

Other particular embodiments of the present invention include a stapleinsulation form for use with a staple to provide an insulated staple,the staple having a width and a bight section extending between a pairof legs, the legs extending from an underside of the bight section, theinsulation form comprising a crown section having a width and a topside, wherein the top side is configured for operable association withthe underside of the staple bight section; and, wherein the crown widthis less than or equal to a width of a staple.

Other particular embodiments of the present invention further include amethod of discharging a fastener from a nailer or stapler device, themethod may include the step of providing a fastener-discharging devicehaving a solenoid, a flash capacitor, a direct current power source, anda control circuit, the flash capacitor operating at 400 or moremicrofarads and having a charging capacity of at least 180 volts, andthe power source having a charging capacity of at least approximately 12volts. Particular embodiment of the present invention may furtherinclude the steps of charging the capacitor within 20 seconds or lessfrom the direct current power source from no charge to at least 180volts, the charging occurring by way of a charging circuit of thecontrol circuit, and discharging the capacitor in full to operate asolenoid, the solenoid thereby driving a striker to discharge afastener, wherein the capacitor is charged and discharged within 20seconds or less.

Particular embodiments of the present invention may further includemethods for securing a target object to a work piece, the method mayinclude a step of providing a stapler having a staple striker, thestaple striker having a non-linear bottom edge. Other steps may includealigning the stapler over a target object, the target object beinglocated on a work piece, and engaging a staple with the staple strikerto discharge staple about the target object and into contact with thework piece. Another step may include deforming the staple with thestriker bottom edge while the striker drives the staple into the workpiece.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more detailed descriptionsof particular embodiments of the invention, as illustrated in theaccompanying drawing wherein like reference numbers represent like partsof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an exemplary embodiment of the fastener drivingdevice of the present invention.

FIG. 2 is a bottom perspective view of the device shown in FIG. 1, inaccordance with an exemplary embodiment of the present invention.

FIG. 3 is a top perspective view of the device shown in FIG. 1, inaccordance with an exemplary embodiment of the present invention.

FIG. 4 is an internal side view of the device shown in FIG. 1, inaccordance with an exemplary embodiment of the present invention.

FIG. 5 is a perspective side view of the device shown in FIG. 1, showinginternal components thereof, in accordance with an exemplary embodimentof the invention.

FIG. 6 is a side perspective view of the drive assembly, in accordancewith an embodiment of the device shown in FIG. 1.

FIG. 6A is a partial side perspective view of the drive assembly shownin FIG. 6, showing an alternative embodiment of the drive assembly, inaccordance with an embodiment of the device shown in FIG. 1.

FIG. 7 is a side view of the fastener striker, in accordance with anembodiment of device disclosed in FIG. 1.

FIG. 8 is a top view of the fastener striker shown in FIG. 7.

FIG. 9 is a perspective view of the coupler block, in accordance with anembodiment of device disclosed in FIG. 1.

FIG. 10 is a bottom view of the coupler block shown in FIG. 9;

FIG. 11 is an exploded view of the fastener housing, in accordance withan embodiment of the device disclosed in FIG. 1.

FIG. 12 is a bottom view of the device showing the main rail partiallyremoved, in accordance with an embodiment of the device shown in FIG. 1.

FIG. 13 is side view of the main rail showing the spring engaged withthe pusher, in accordance with an embodiment of the device shown in FIG.1.

FIG. 14 is an end view of the main rail, in accordance with anembodiment of the device shown in FIG. 1.

FIG. 15 is a perspective view of the heat sink, in accordance with anembodiment of the device shown in FIG. 1.

FIG. 16 is a side view of a staple insulation form, in accordance withan embodiment of present invention.

FIG. 17 is a perspective view of a staple insulation strip, inaccordance with an embodiment of the present invention.

FIG. 18 is a cross-section view of the staple insulation strip shown inFIG. 17 where the cross-section is taken through a deformation void, inaccordance with an embodiment of the present invention.

FIG. 19 is a side view of an insulated staple, in accordance with anembodiment of present invention.

FIG. 19A is a side view of an insulated staple driven into a work pieceto secure a target object, in accordance with an embodiment of thepresent invention.

FIG. 20 is a perspective view of an insulated staple clip, in accordancewith an embodiment of the present invention.

FIG. 21 is a cross-section view of the insulated staple clip shown inFIG. 20 where the cross-section is taken through a deformation void, inaccordance with an embodiment of the present invention.

FIG. 22 is blown up view of Section A shown in FIG. 21.

FIG. 23 is an end view of an embodiment of the device shown FIG. 1, madein accordance with the present invention, where the device is capable oftilting side-to-side.

FIG. 24 is an end view of an embodiment of the device shown FIG. 1, madein accordance with the present invention, where the device is capable oftilting side-to-side.

FIG. 25 is a top-side perspective view of an embodiment of the deviceshown FIG. 1, made in accordance with the present invention, showing avariable power sensor capable of varying power based upon the height ofa target object to be secured, and a low staple sensor.

FIG. 25A is a bottom-side perspective view of an embodiment of thedevice shown FIG. 1, made in accordance with the present invention,where the device includes variable power sensors that are capable ofvarying power based upon work piece hardness and/or the height of atarget object to be secured.

FIG. 26A-D is a view of a control circuit in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

A fastener driving device 10 is generally discussed herein, which mayoperate from a DC power source and is capable of discharging fastenersat elevated power levels, at quicker cycle times, and over an extendedperiod of time on a single power source charge. Device 10 may be astapler, a nailer, or any other fastener driving device.

In an exemplary embodiment, as shown in the FIGS. 1-26D, device 10comprises a direct current (DC) powered stapler 10. The DC-poweredstapler 10 is capable of driving staples at reduced cycle timeintervals, such as between two (2) and three (3) seconds when fullycharging and discharging a 360 volt, 1200 uF (microfarad) flashcapacitor. In another embodiment, the cycle time is approximately around1.5 seconds when fully charging and discharging a 180 volt, 1200 uFcapacitor. Further, on a single battery charge, the device 10 is capableof making well over 900 shots with a 12-cell 14.4 volt Ni-Cad batterypack, which is generally well over 2 days of work for a commercial user.The number of shots may increase when using a similar Li-ion battery.

In this exemplary embodiment, device 10 is also capable of drivingstaples that comply with UL 2239 requirements, including withstandingthe 7.2 pull test, which requires the driven staple to remain intact for5 minutes while being subjected to a 50 pound load. To achieve this, thedevice 10 generally provides higher power to effectively drive staplesto appropriate depths in softer or harder target mediums (“workpieces”), such as, for example, Douglas fir and yellow pine (a hardstud-grade wood). Such staples, in particular embodiments, may includestaples having at least a 9/16 inch leg height.

To effectively perform in commercial conditions, the device 10 may becapable of discharging staples into various target work pieces (hereinafter referred to as “work pieces”), such as varieties of wood, plastic,and composite joists, framing, studs, and other structures to securevarious target objects, such as cables, conduit, and wire. Becausestaples may need to be driven into objects that are more or lessresistant (i.e., harder/denser or softer/less dense), device 10 mayprovide elevated driving power, which may be variable. In otherembodiments, device 10 may be capable of storing and discharging nails(nails and brad nails) and other driven fasteners.

In particular embodiments, the fastener driving device 10 utilizes asolenoid 12 and a high voltage capacitor 100 to drive insulated andnon-insulated staples into a desired object. The fastener driving device10 may also utilize other drive-generating sources, such as, forexample, a fly wheel, a compressed spring, a pneumatically or combustiondriven piston, to drive the fasteners.

In one embodiment, device 10 generally includes a solenoid 12, a driveassembly 20, a fastener housing 40, a high voltage capacitor 100, apower source 104, control circuit 110, and a body 58.

Device 10 may generally utilize a solenoid 12 to drive a fastener, suchas an insulated or non-insulate staple. As shown in FIG. 6, solenoid 12generally includes a coil 13, a ferrous slug referred to as an armature(or plunger) 14, and a pushrod 16. When electrical current is passed tosolenoid 12, the coil 13 is energized. Subsequently, the energized coilproduces a magnetic field that attracts armature 14 inward toward thecenter of the magnetic field (i.e., the coil). This causes pushrod 16 totranslate downward, which provides the force transferred to the driveassembly 20 for driving a target fastener into a target work piece. Thestrength of the magnetic field and the corresponding plunger drivingforce may be increased or decreased by increasing or decreasing thevoltage, respectively. Each solenoid generally includes a maximumstroke, which is the maximum distance an armature 14 or pushrod 16 maytravel in any one direction. It is contemplated that a solenoid may havean end stroke end that provides a stroke distance that is different thanthe maximum stroke. Further, the end stroke may be adjustable. In oneexample, the end stroke is specified to end at the coil's maximummagnetic field. If the armature 14 travels beyond the intended endstroke or position, it may be pulled back by the coil if desired. A stop18 may be included within the solenoid housing to limit the stroke andprotect the housing from armature 14 impact. In one embodiment, stop 18is a spring or bumper formed of a resilient elastic material.

In one embodiment, device 10 may include an armature-retention mechanismto maintain armature in a ready-position, in which the armature 14awaits deployment towards coil 13 for fastener discharge. In oneembodiment, the armature-retention mechanism comprises a retaininggroove 15 a located along a surface of armature 14, and one or morespring-loaded ball bearings 15 b, located within housing 58, that engageretaining groove 15 a when armature 14 is in a desired position, such asa ready-position (ready to fire). This allows armature 14 to be retainedin a pre-firing position away from the solenoid's coil 13. This may aidin preventing unintentional staple discharge or separation. Further,such mechanism may retain the armature 14 in a ready-position when thecoil is initially energized, so that armature 14 is not drawn toward thecoil 13 in a gradual manner. Instead, attractive forces build betweenthe coil 13 and armature 14 until the forces are able to overcome theretention forces applied by the spring-loaded ball bearings 15 b. Uponrelease by the ball bearings 15 b, a sling-shot effect may be achieved.This causes the armature 14 to be immediately released at a higher forcewhich increases the driving force and momentum provided by pushrod 16.Finally, by utilizing a spring-loaded retention means as describedherein, a user does not have to release the armature, but rather, thearmature 14 is release automatically when the solenoid-generated forceovercomes the spring forces. It is contemplated that other means may beused to retain armature 14 in a position, such as spring-loaded clips,resilient gaskets or clips, or other mechanical or electromagneticmeans.

Drive assembly 20 engages pushrod 16, and transfers the force andmomentum generated thereby to discharge a target fastener. As shown inFIG. 6, drive assembly 20 includes a striker 22, striker guide 26,return spring 28, and plunger coupling 30. Plunger coupling 30mechanically associates striker 22 with pushrod 16. As the forcegenerated by pushrod 16 is transferred through coupling 30, striker 22is forced downward through the striker guide 26. Ultimately, a bottomedge 23 a of striker 22 contacts a target fastener, such as a staple,for discharge. If the fastener is part of a clip, striker 22 causes thetarget fastener and any insulation associated therewith to shear fromthe clip.

Striker 22, in one embodiment shown in FIGS. 7-8, is the component thatengages a target fastener via a bottom edge 23, and discharges thetarget fastener into a desired work piece. Striker 22 operates withinstriker guide 26 by virtue of a track 27 a, which extends longitudinallyalong striker guide 26. Staples or fasteners are discharged outwardlyfrom a bottom of striker guide 26, by way of track 27 a. Striker 22 isconstrained within track 27 a by retention member 27 b, which slidesover the top of striker guide 26 and about striker 22 . It iscontemplated that side portions of track 27 a may extend into guide 26,so that striker 22 is constrained within track 27 a by guide 26, withoutuse of member 27 b. Arrangements other than those discussed may also beused to guide striker 22 along a track between pre-firing and dischargedpositions.

Traditionally, staples strikers 22 have provided linearly flat bottomedges 23. This generally allows the flat bottom edge 23 of striker 22 toevenly apply a driving force across a flat staple bight (or crown) 84.However, it may be desirous to provide a more shaped staple (insulatedor non-insulated) 60, 80 when securing particular target objects to awork piece. Therefore, is may be desirous to deform a staple (insulatedor non-insulated) 60, 80 about a target object, such as cable, conduit,wire, or the like. This may occur while the staple 60, 80 is beingdriven into the work piece. The deformed staple may improve securementof the target object by providing a shape having more contact surfacearea for resisting any movement of the target object, while reducing thelikelihood of damaging the target object if the staple is overdriven, asthe force is now dispersed along a larger area.

To provide a deformed driven staple (insulated or non-insulated), thebottom edge 23 of striker 22 may include, or form, a desired shape. Inone embodiment, the bottom edge 23 includes an arcuate shape to allowthe staple to form about the object being secured. It is contemplatedthat the shape of bottom edge 23 may be symmetrical or asymmetrical, ormay comprise any desirous shape, such as, without limitation, an arc, ahalf-circle, or a triangle (i.e., an inverted V-shape), or may comprisean asymmetric, linearly-inclined (guillotine) edge. One purpose of thisasymmetric striker bottom edge 23 may be to increase the shear forceapplied to the staple and/or insulation, for improved shearing of thestaple and/or insulation from a strip or clip. An asymmetrically arcuateor inverted V-shaped striker 22 combines the benefits of the asymmetricstriker, with the benefits of a shaped staple to provide a staple thatcan better conform to the shape of a target object while potentiallyreducing the amount of power needed to shear any staple or insulationfor discharge.

When the shaped striker 22 engages a staple (insulated or non-insulated)60, 80, the shaped bottom edge 23 engages the staple bight 84. Bight 84may be deformed generally into the shape of bottom edge 23, or someother shape that is desirable. For example, if a bottom edge 23 havingan inverted V-shape does not form a staple bight 84 into the invertedV-shape, it may instead form the bight section 84, or a portion thereof,into a more rounded shape. The ability of a staple 60, 80 to deform, andthe extent thereof, is in part dependent upon the material and design ofstaple 80 and any insulation 62, and the resistance provided by thetarget object. It is contemplated that bottom edge 23 may beapproximately as wide as or wider than the width of staple 60, 80 (i.e.,the width of bight 84); however, it is contemplated that bottom edge 23may have a width less than the staple 60, 80 width. A dischargedinsulated staple 60 is shown in FIG. 19A, in an exemplary embodiment,where it is shown to have been driven into a work piece by a shapedstriker. The insulated staple 60 is also securing a target object. Anon-insulated staple 80 would look similar to FIG. 19A, except that noinsulation 62 would be present so to allow staple 80 to instead engagethe target object.

Striker 22 may also include a gusseted portion 24 that extends along alength (height) of striker 22, and outward from a transverse plane ofstriker 22. This gusseted portion 24 increases the column strength ofstriker 22 to better resist any buckling of striker 22 under the highforces generated by this device 10 the to drive the target fasteners.Forces experienced by the striker 22 may vary, according to the powerprovided by the capacitor 100, which may depend on various factors, suchas the hardness of the target medium, the desired fastener drive depth,and whether the striker 22 is to bend or deform a discharged stapleabout the target object that the staple is securing.

Striker guide 26 provides a bottom edge 26 a for engaging a mediumtargeted to receive a discharged fastener. This bottom edge 26 aprovides a point of contact between the target medium and device 10,which allows a user to forcefully direct the device 10 against thetarget medium in anticipation of fastener discharge. The engaging bottomedge 26 a may be non-linear, in that the bottom of the guide 26 mayinclude a recessed shape or shapes 26 b, which may be similar to a shapeof the striker bottom edge 23. This recess may allow a target objectthat is to be secured by the fastener to enter the guide 26 and alignthe target object between the legs of a discharging staple, which mayprevent any potential damage to the target object. In this instance, therecess 26 b is an alignment guide 54, as discussed below. Further, fullconsumption of the target object within the recess 26 b may allow thebottom edge 26 a of guide 26 to continue its engagement with the workpiece. Finally, placement of a target object within the recess 26 b mayallow the target object to engage a safety blade 56, which closes asafety switch 174. Safety switch 174 may have to be closed before astaple can be discharged. Device 10 may still remain in contact with theunderlying work piece for driving support. Striker guide 26 may alsoguide a fastener deployed from its stored position through completedischarge and engagement with the target work piece.

Coupling 30, in one embodiment shown in FIGS. 9-10, comprises a block 32that accepts a terminal end of pushrod 16. Pushrod 16 may be securedwithin block 32 by any acceptable means, such as, for example, anadhesive, a fastener or pin, friction, or any other mechanicalinterference. A ridge 33 may be included to engage and constrain pushrod16 within block 32. In one embodiment, a clip 34 is inserted throughapertures in block 32 to engage flanges 25 of striker 22. Flanges 25allow clip 34 to constrain striker 22 within the drive assembly 20, andreturning striker 22 to a ready position after staple discharge. It iscontemplated that other known or unknown means of operably couplingstriker 22 to pushrod 16 may be used, such as, for example, a pin, bolt,bracket, or weld.

Spring 28 operates to return the pushrod 16 and armature 14 to a readyposition, which may include the engagement of ball bearings 15 b withretaining groove 15 a. In one embodiment, spring 28 is a compressionspring that extends below coupling 30, and operates between coupling 30and the striker guide 26. Spring 28 may be a tapered spring, whichreduces the compressed height of the spring 28 and, consequently, mayreduce the overall height of device 10. In other embodiments, spring 28may be located in other places, such as near the top of solenoid 12 orarmature 14. Spring 28 may also be a torsion spring or an extensionspring, which may be located, for example, atop solenoid 12 inassociation with armature 14 or between coupling 30 and solenoid 12.

Typically, in an effort to drive fasteners into tight spaces and toprovide improved visibility of fastener alignment and discharge, strikerguide 26 may be located close to the front tip of stapler/device 10.This is often called a blunt nose orientation. In one embodiment,generally shown in the FIGS. 1-5, the longitudinal axis of the solenoid12 (or the pushrod 16) generally extends in a vertical direction withindevice 10 and is generally perpendicular to the main rail 42, orparallel to the direction of staple discharge. Because the solenoid 12is much wider than pushrod 16, it may be difficult to discharge staplesat or near the front-most tip of device 10, which may make it difficultto discharge fasteners in tight or abutting locations. In an embodimentexemplarily shown in FIG. 6A, a cantilever 36 may generally extend fromthe pushrod 16 in a transverse (lateral or longitudinal) direction ofdevice 10, towards the front of the device 10 to move striker 22 and thefastener discharge closer to the tip or front of the device 10.Consequently, when pushrod 16 is actuated, the displacement of thepushrod 16 is transferred to striker 22 via cantilever 36. Cantilever 36may comprise a coupler extending between striker 22 and pushrod 16 ormay comprise an arcuate striker 22, which may be flexible. In analternative embodiment, the solenoid 12 may be inclined with regard tothe main rail 42, or the direction of staple discharge. This orientationcould eliminate the need for the cantilever 36, or in the very least,require an arcuate or angled mechanism to transfer the driving force tothe fastener to allow the fastener to engage the work pieceperpendicularly. The arcuate or angled mechanism, which may be flexible,may comprise striker 22 or another mechanism.

Fasteners are generally contained within a fastener housing 40. Housing40 comprises a design that provides both structural integrity andrigidity, and interchangeability. In one embodiment, shown in FIGS.11-14, housing 40 may store insulated and/or non-insulated staples andincludes a removable main rail 42 that operates within a cavity definedby top rail 44 and the bottom of the body 58. Top rail 44 generallyattaches to striker guide 26 by way of tabs 49, which are inserted intoapertures 27 c of striker guide 26, and secured by way of clips 49 a. Itis contemplated that any other known means, such as fasteners,adhesives, or the like may be used to secure tabs 49 to striker guide26. A removable fastener may also be used to more easily remove strikerguide 26 from device 10. In one embodiment, a de-sta-co clamp or thelike may be used to removably secure top rail 44 to striker guide 26.

In particular embodiments, bottom plate 48 is attached to the bottom ofmain rail 42, and may support insulated and/or non-insulated staplesstored along the main rail 42. Main rail 42 generally maintains thestaples, whether the staples are in a unified clip or independentlyexist along main rail 42. Spring 51 maintains pusher 50 in forcefulengagement with the staples along main rail 42, and forcefully directsthe staples into a series of insulated and/or non-insulated staples, andtowards the striker 22 for discharge. Pusher 50 may include a tab 52that operates within a groove 45 of top rail 44, where the translationof tab 52 and, therefore, pusher 50, is maintained along a single pathdefined by groove 45. It is contemplated that other means may be used todirect or control the translation of pusher 50.

Fastener housing 40 may also include windows 46 to visibly determine if,and approximately how many, fasteners remain in device 10. In oneembodiment, at least two windows are located along at least one of theopposing longitudinal sides of top rail 44. Although each window 46 maybe capable of displaying any desired number of staples, in oneembodiment each window 46 is capable of displaying 22 staples. In oneembodiment, fastener housing 40 is capable of storing 97 staples. Inthis embodiment, a window 46 is positioned along the length of top rail44 so that a maximum of 17 staples may remain hidden within housing 40,that is between the window 46 and the striker guide 26. Therefore, whenthe staples housed within housing 40 are no longer visible in a window46, the housing 40 is capable of accepting two standard 40-count stapleclips (or one standard 80-count clip) since housing 40 is capable ofholding 97 staples (2-40 count clips equals 80 staples, plus the maximumof 17 remaining equates to a maximum of 97 staples, which is within thecapacity of housing 40). This concept and strategy may be employed withany capacity housing 40. Further, any number of windows 46 may exist,which may also be located at any location along housing 40.

In one embodiment, housing 40 may be capable of storing and discharginginsulated and/or non-insulated staples. In achieving this dualcapability, in one embodiment, non-insulated staples may rest along atop surface of bottom plate 48, while insulated staples may rest along atop surface of main rail 42. It is also contemplated that insulated andnon-insulated staples may both rest on either the top 42 a of main rail42 or on the bottom plate 48. Because these surfaces may have to resistthe shearing forces applied by striker 22 to staples for separation anddischarge, it may be desirous to form these surfaces or elements from,or provide additional elements made from, harder or more durablematerials. Accordingly, bottom plate 48 and at least a top portion 42 aof main rail 42 may be formed of steel, or any other durable metal orplastic to improve the durability of device 10 by better resisting theforces applied by striker 22.

In other embodiments, separate staples and staple insulation may beinserted into housing 40 to ultimately provide a driven insulatedstaple. In these embodiments, the staples and insulation may be storedseparately within housing, where the insulated staple is formed at thetime of discharge, or each may be stored together (with or without beingattached to one another) for ultimate discharge. Insulated andnon-insulated staples may be accepted individually or as a plurality inclip form. To provide this capability, a single pusher capable ofpushing both the staples and insulation may be provided, or a separatepusher may be provided for the insulation.

Because various types of fasteners may be used in device 10, it iscontemplated that housing 40 or a portion thereof, such as the main rail42, may be removable so to provide interchangeable magazines containingdifferent types of fasteners. This allows a user to quickly remove afirst magazine that is empty or that contains one type of fastener, suchas insulated staples or brads, and quickly insert a second magazine thatis full or that contains a second type of fastener, such asnon-insulated staples. In one embodiment, main rail 42 and top rail 44are removable, such as a single magazine unit, by detaching top railtabs 49 from striker guide 26.

In the embodiment shown in the figures, the fasteners may be insertedinto the housing 40 either through an aperture 59 in the bottom of body58, or directly onto the main rail 42, when main rail 42 is retractedfrom top rail 44. Loading the fasteners into the body aperture 59 iscommonly referred to as bottom loading. Aperture 59 may also be usefulin providing access for the removal of any fastener jams occurring nearor within the striker guide 26.

The exterior end of the main rail 42 may include a grip 43 a to bettergrasp and retract main rail 42. One or more clips 43 b may be includedto secure the main rail 42 to device 10 for operation of device 10. Theinternal end remains open for the purpose of exposing fasteners intostriker guide 26 for engagement with striker 22. In other words, pusher50 directs the fasteners toward the internal end of main rail 42 toready a fastener for discharge. Top rail 44 may coordinate with strikerguide 26 to achieve an integrated housing 40.

In one embodiment, device 10 may include a low staple sensor 108a thatmay determine if there is a low quantity, and/or no quantity, offasteners remaining within fastener housing 40. It may be desirous toknow whether the housing 40 is empty, to prevent any dry firing (firingwithout a fastener) to prevent damage to device 10 and/or any targetobject adjacent the fastener discharge of device 10. This sensor maycomprise any sensor capable of sensing staples within sensor housing 40,and may be, for example, an optical or physical sensor. In oneembodiment, sensor 108 a is a physical sensor that engages staplesthrough an opening 108 b in fastener housing 40. If there is not stapleto engage, sensor 108 a indicates such to control circuit 110. Uponindication, control circuit 110 knows how many fasteners remain, andwill count the quantity of subsequent fastener discharges to determinewhen no fasteners remain. When determining that no fasteners remain,control circuit 110 will prevent the stapler from firing until staplesare replaced.

Along the bottom side of the driving device 10 where fasteners aredischarged, there may be any number of alignment guides 54 that functionto align the fastener with respect to a target object, such as a cable,conduit, wire, pipe, etc. The alignment guides 54 may also serve to gripthe cable, etc. so that the user can pull a target cable, wire, or thelike taught prior to deployment of a fastener, for the purpose ofeliminating any slack in the target object. Today, electricians have topull on the cable prior to and independent of securing the cable with astaple. Therefore, the guides 54 would assist users by eliminating astep in the process and freeing a hand for other uses.

In particular embodiments, striker guide 26 extends outwardly beyond thebottom side of the stapler 10 to include a recess 26 b, which functionsas, or forms, an alignment guide 54. In one embodiment, a guide 54positions a target object relative to a staple discharge, so to directthe discharged staple legs about a target object, and thereby reducingthe chance that the discharged staple would damage the target object,which may be an object, such as a cable or wire, being secured to a workpiece. In other embodiments, guides 54 may align a target object for thepurpose of driving a fastener through the object, such as for securementthereof, which is different than protecting the object from fastenerpenetration. Further, guides 54, including striker guide 26, may beremovable to allow the use of different guides, which may bespecifically used in association with different types of target objectsor different applications. In particular embodiments, striker guide 26may comprise multiple interconnected segments, wherein one segmentincludes an alignment guide 54, which may be removable. Still further,removable fastener magazines (discussed below) may include differentguides 54 for use with specific fasteners or applications. For example,device 10, or a removable fastener magazine, may include guides 54 foruse with specific fasteners for securing specific specifically securing,for example, low voltage wires, such as Category 5-Cat 5, Co-ax, andtelephone wires, metal clad (MC), armored cable (AC), or flexiblemetallic conduit (FMC), Electrical Metallic Tubing (EMT), rigid conduit,PVC conduit, or copper or PVC water pipe. Device 10 may also includelaser guides to improve a user's ability to align the device 10 with atarget object or target work piece. Finally, device 10 may include asensor that determines whether a target object is centered within aguide 54. This guide 54 may be located near the staple discharge. Aspecially contoured or narrow safety blade 56 may accomplish thisfunction and therefore become this centering sensor.

As shown in FIGS. 1-5, a safety blade 56 may be provided and locatedalong the bottom side of the stapler 10, which may trigger a safetyswitch 174 before firing device 10. This may help to ensure that device10 is properly aligned and/or engaged prior to firing. In oneembodiment, blade 56 is located near or adjacent to an alignment guide54 or striker guide 26. This better allows blade 56 to verify that thetarget object is most appropriately aligned with the fastener to bedischarged. It is contemplated, however, that safety blade 56 may belocated in other desirous locations.

In one embodiment, blade 56 has a linearly flat bottom edge that extendsacross the width of a target object. Therefore, blade 56 may extendacross the width of an alignment guide 54, a striker guide 26, or astriker guide bottom edge 26 b. By providing this flat blade design,blade 56 will recognize any object within striker guide 26 or alignmentguide 54, regardless of whether the object is narrower that any suchwidth, and regardless of whether any such object is centered within suchwidth. For example, a narrower or pin-like safety blade 56 may notrecognize a narrower object located within striker guide 26 or alignmentguide 54. Of course, it is contemplated that a differently shaped bottomblade bottom edge, or a narrower blade design, may be desirous, such aswhen one desires that an object be specifically located within guide 54,such as being centered or off-centered, or to recognize only certaintypes of objects within guide 54. Alternative bottom edges include,without limitation, arcuate or linearly angled edges.

It is contemplated that after safety switch 174 is initially triggered,multiple fastener shots may be deployed, or, it may be required thatsafety switch 174 be reset and re-triggered after a single shot toprevent accidental subsequent discharges. It is also contemplated thatsafety blade 56 and safety switch 174 may operate in a “bump” mode,which allows the user to hold down the trigger and fire the gun just bydepressing the safety blade 56. In one embodiment, the securing ofcables and the like does not include “bump” mode, as it is may bedangerous and not required for such application.

The internal components of the stapler 10 may be contained in a body 58,which may generally form a shell (or compartment) and include anergonomically designed handle. The body 58 may comprise a pair of matinghalves or portions, a clam shell, or any other number of interconnectingportions. Device 10 may also include a handle 55 a, which may be formedas part of body 58, or may be separately manufactured for attachment tobody 58. Device 10 generally includes a trigger 55 b to initiate atrigger switch 172 for fastener discharge. The trigger 55 b is locatedin the vicinity of the handle 55 a, and in one embodiment, isergonomically located along a bottom, front portion of the handle 55 afor ease of use and to better facilitate single hand operation of thedevice 10 . The body 58 may be formed of plastic, or any other desiredmaterial, in whole or in part. Of course, the body 58 may also be formedof multiple materials, as certain materials may be desired in certainareas, such as the handle portion 55 a. It is contemplated thatovermolding, or any other process similar in result, may be used to addor include decorative or functional features or materials to desiredportions of the body 58. One such example includes applying overmoldedEPDM and/or TPE to the handle 55 a for improved gripping performance andreducing the impact energy transmitted to the user. Device 10 may alsoinclude a belt clip 57, which may be mounted on either side of body 58,as desired by a user of device 10.

In particular embodiments, shown exemplarily in FIGS. 23-24, it iscontemplated that the device 10 may pivot sideways to lower itseffective height or to otherwise the device 10 to enter tight spaces,such as closely positioned studs. Accordingly, device 10 includes a topportion 58 a that tilts or rotates in relation to a bottom portion 58 b.To achieve this, pivotable joints may exist between top 58 a and bottom58 b, and a flexible striker 22 and/or a flexible or rotatable couplingmay exist within drive assembly 20 to allow striker to engage a staplein any tilted or untitled position of body 58. It is contemplated thattop portion 58 a may rotate any amount in relation to bottom portion 58b, for example, without limitation, ±15°. Not only does this provideentry into tight spaces, it also allows the fastener to be dischargednormal to the target or the bottom of device 10. This may be achievedinternally by using a flexible striker 22 or pushrod 16, or a flexibleplunger/striker coupler. In the alternative, it is contemplated that thedevice 10 may pivot from front to back, which may reduce the effectivewidth of the device 10, while the fasteners may or may not discharge atan angle with regard to the receiving surface/object.

As mentioned above, in one embodiment, the fasteners used in drivingdevice 10 are staples. In the embodiments of device 10 shown in thefigures, the driving device is capable of storing and discharging bothnon-insulated staples 80 and insulated staples 60. In other embodiments,driving device 10 may be limited to discharging either insulated 60 ornon-insulated staples 80. The staples 80, which may be used to forminsulated staples 60, may comprise any commercially available staples,or may be specially designed for use in a particular device 10. In theembodiment shown in the figures, insulated and non-insulated staples 60,80 may be provided as individual staples, or in clip form.

Insulated and non-insulated staples 60, 80 are generally discharged fromdevice 10 into a target work piece to secure a target object thereto. Inthe embodiment shown, driving device 10 utilizes insulated andnon-insulated staples 60, 80 to secure any commercially availablesheathed or unsheathed cable or wire, such as, without limitation: 14-2,14-3, 12-2, 14-4, 12-3, 12-4, 10-2, 10-3, stacked (two) 14-2, stacked(two) 12-2 NM wire (Romex); Cat-5; and other low voltage wire. It isalso contemplated that device 10 may utilize staples or other fastenersto secure conduit or pipe, or any other similar product, such as,without limitation: armored cable and conduit (MC, AC, and FMC); EMT;rigid conduit; PVC conduit; and/or copper or PVC water pipe, or anyother similar product(s).

As stated above, the one embodiment of device shown in the figures iscapable of discharging both insulated and non-insulated staples 60, 80.As shown in exemplary embodiments in FIGS. 16-22, insulated staples 60generally comprise an insulation form 62 and a staple 80, with the form62 being placed in cooperative association with the staple 80. Insulatedstaples 60 may exist individually or with a plurality of other staples60 in the form of a clip 61. While clip 61 may be assembled from aplurality of individual insulated staples 60, in one embodiment, clip 61is formed by associating a strip of insulation forms 64 with a strip ofstaples 82.

Referring to the embodiments shown in FIGS. 16-22, insulation forms 62,whether in individual 62 or strip 64 form, are generally placed inassociation with a staple 80, and more specifically, with the undersideof the staple bight 84. It is contemplated that any suitable material,such as plastic, polymer, elastomer, metal, paper or cardboard, orcomposite may be used. In one embodiment, insulation 62, 64 comprisesinjection molded thermoplastic or molded elastomer. In particularembodiments, forms 62, 64 comprise nylon 66, nylon 11, nylon 12, oracrylonitrile butadiene styrene (ABS). In particular embodiments,insulation 62, 64 is made of electrically non-conductive material.

As suggested earlier, insulators 62 may be produced as individualsegments for use with individual staples 80, or may be formed intostrips 64 comprising a plurality of joined and separable insulator forms62. Each of the forms 62 may be designed to generally correspond to anindividual staple 80, whether the staple 80 is alone or part of strip82. In particular embodiments, the thickness of insulator 62 is equal toor less than the thickness of staple bight 84. Consequently, inparticular embodiments, an insulation strip 64 may include a quantity offorms 62 that is equal to the quantity of staples 80 in a staple strip82. Further, in particular embodiments, the length of insulation strip64 may be substantially the same as a corresponding staple strip 82,where substantially the same includes insulation strips 64 that areshorter than staple strip 82 by less than the thickness of a staple 80,since tolerances or offsets located at one or both ends of insulationstrip 64 may provide a slightly shorter length of strip 64 even thoughstrip 64 still includes a quantity of forms 62 substantially equal to,and in alignment with, the staples 80 in strip 82. Therefore, it iscontemplated that insulation strip 64 may manufactured for use with anycommercially available staple strip 82. Due to the differences intolerances between the staples 80 and the insulators 62, it may bedesirable to limit the number of insulators 62 produced within a strip64 to maintain or control strip dimensions. In particular embodiments,strip 64 includes between 25-50 forms 62. In more specific embodiments,strip 64 includes 40 insulation forms 62.

Each insulation form 62 generally includes a crown 66, and a pair oflegs 68 extending there from; however, it is contemplated that form 62may only include a crown 66 without one or more legs 68. The crown 66may correspond to the bight 84 of staple 80, while legs 68 maycorrespond to legs 86 of staple 80. Insulation form 62 may includedeformation voids 70, which, for example, may be contained within form62 or located along a surface thereof. In one embodiment, one or moredeformation voids or recesses 70 are located along an upper surface ofcrown 66. Voids 70 may comprise notches or grooves that allow the form62 to bend and contort so it may adapt to the cable, wire, or othertarget that is being secured by an insulated staple 60. The voids 70allow the insulation form 62 to be made from more durable and hardermaterials, which otherwise may not appropriately bend without theinclusion of voids 70. In one embodiment, three voids 70 are equallyspaced across crown 66, where one void is located near the center ofcrown 66 to encourage crown deflection about the central void 70, andone void 70 is located near each leg 68 to encourage further deflectionof the crown and deflection or translation of the legs 68 in relation tocrown 66. However, it is contemplated that no voids may exist, or thatone or more voids may exist along crown 66. In one embodiment, each void70 comprises an approximately 0.025 inch half circle; however, othersizes and shapes may be used to form each void 70 and to achieve thedesired deflection, which may be based on the amount of driving force.Further, the sizes may vary, such as, for example, according to thematerial used to create each form 62. It is contemplated that the shapesof voids 70 may include, without limitation, half circles or ovals,squares, triangles, and rectangles.

The bottom side 72 of crown 72 is shaped to deter any abrasion orcutting of the target object to be secured by the staples. The areabetween the bottom side 72 and each of the legs 68 may include a gusset74. Gusset 74 controls deflection and aids in deterring any tearing ofthe insulation form 62 during deflection, such as between the crown 66and legs 68. Gusset 74 may comprise any sized shape, which may include,for example, a radiused or linearly angled form (i.e., a triangle)extending between the bottom section 72 or crown 66 and each leg 68.

At the bottom of each leg 68 is a tip 69. Each tip is designed to besufficiently pointed, in an attempt to avoid any buckling of each leg 68as it enters the target work piece. The target work piece may be anydesired target that the staple is to enter and secure to, such as, forexample, wooden, plastic, concrete, or composite studs or planking. Itis contemplated that legs 68 may not exist, or that legs 68 may besufficiently short so that each is not necessarily capable of enteringthe target work piece. Further, it is not necessary that insulation form62 be symmetrical, as asymmetrical geometry or deflection may be desiredbased upon an oddly shaped target object or target work piece.

In a strip 64, each form 62 may be spaced from each adjacent form 62 bya particular spacing 78. The value of spacing 78 is selected so tosubstantially align, as desired, each form 62 with each correspondingstaple 80. Generally, forms 62 are centered along the width of staples80; however, other non-centered alignments are contemplated. Connectors76 may extend between adjacent forms 62 to assemble an array ofinsulator forms 62 into a strip 64. Connectors 76 may comprise one ormore extensions (as shown in the figures), or connectors 76 may comprisea continuous or discontinuous thin band that extends about the boundarybetween adjoining forms 62. Connectors 76 also align each form 62 witheach corresponding staple 80 as desired. In an alternative embodiment,each form 62 may substantially abut each adjacent form 62 without theuse of connectors 76, meaning that each of the crown 66 and/or legs 68may be directly attached to an adjacent crown 66 or leg 68,respectively. Finally, each leg may have a tapered width, where eachsuch taper corresponds to a draft angle 79. This may improve the removalof insulation form 62 or clip 64 from a mold. Also, by thinning thecross-section closer to the crown 66, deflection may be bettercontrolled as deflection may be directed to the thinner cross-section,which has a lower bending modulus.

As stated above, the individual forms 62 may be interconnected via oneor more connectors or joints 76. Connectors 76 generally extend betweenforms 62, and may include a cross-section that is sized and shaped toadequately allow a form 62 to shear from (i.e., detach from) a strip 64when engaged by a stapler device for discharge. In the embodiments shownin the figures, connectors 76 are projections, each of which have across-sectional area of approximately 0.0003 square inches; however, itis understood that this area may comprise any area, as such area willvary with the material used to form connector 76 and the amount ofshearing force exerted by the stapler device 10. Further, connectors 76may comprise any shape and any length desired for an application. In oneembodiment, connectors 76 may constant or variable cross-section thatincludes one or more shapes, such as, for example, a square,rectangular, triangular, circular, semicircular, or oval. Further,connectors 76 may extend between the individual forms 62 in a linear,angular, arcuate, or V-shaped (or inverted V-shaped) direction.

In various embodiments, insulators 62 may be extruded and include aU-shaped or V-shaped profile, and/or having legs that flare out. It isalso contemplated that the insulators 62 may be insert molded, whereinthe staple clip 82 is inserted into a mold (such as a thermoplastic orthermoset mold) and the insulation form material is injected about thestaples to form insulation in association therewith. If insulation 62can be formed discreetly on each staple, this may reduce and/oreliminate the need to shear insulator 62 upon discharge from a fastenerdischarge device, such as device 10. It is contemplated that theinsulator 62 may be solely applied to the underside of the crown or toboth the top and underside.

It is contemplated that a perforating wheel may be run over theinsulation strip 64 before or after application to the staple(s). Theperforating wheel may puncture the strip 64 numerous times at eachjunction to reduce the amount of shearing force required for separationand discharge. This may occur within the stapler 10 or before insertioninto stapler 10, such as during or subsequent to the manufacturing ofinsulation strips 64 or insulated staple strips 61.

In one embodiment, insulated staples 60 are prefabricated, meaning thatinsulation forms 62 are associated with or attached to staples 80,before being loaded into device 10. In forming an insulated staple 60 orclip 61, an insulation form 62 or strip of insulation 64 may be placedin association with, or frictionally, mechanically, and/or adhesivelyaffixed to, a staple 80 or strip of staples 82. For example, theinsulation may be non-adhesively placed within or in association withthe staples, such as within the stapler. Further, the insulation may bepress-fit into the staples, clipped or interference fit to the staples,or the staple legs may be inserted into apertures located within theinsulation.

In one embodiment, insulation 62 or an insulation strip 64 is adhesivelyaffixed to a corresponding staple 80 or staple strip 82. Attachinginsulation 62, 64 to staples 80, 82 may be desirous to maintain thealignment and association between insulators and staples duringdischarge. Generally, adhesive 90 may be applied between the staples 80or strips 82, and the insulation 62 or strips 64. In one embodiment, oneor more beads of adhesive may be located longitudinally between thebight 84 of the staples 80 and the crown 66 of insulation 62. One ormore beads of adhesive may be located longitudinally between one or morestaple legs 86 and insulation legs 68. In one embodiment, the adhesiveis Loctite 326™ and the beads are approximately 0.060 inches wide.However, the adhesive may comprise any other known temporary orpermanent adhesive suitable for maintaining insulation 62 or strips 64in positional association with staples 80 or strips 82. Further, thesize, quantity, and location of adhesive may vary as desired to achievea desired attachment. For example, one or more beads or coatings mayextend between staples 80, 82 and insulation 62, 64. It is alsocontemplated that the adhesive may be applied to one or more of theinsulation forms 62, strips 64, staples 80, or strips 82, and may extendin a continuous or discontinuous manner.

When a strip of insulation 64 is placed within staple strip 82, theinsulation 64 may be specifically placed so that each insulation form 62is aligned with an individual staple 80. To assist in this alignmentprocess, tabs or spacers 77 may extend outwardly at each end of theinsulation strip 64 to a desired distance. The desired distance mayprovide an offset distance 78 from the end of the staple strip 82, or itmay extend to coincide with (i.e., extend flush with) the end of thestaple strip 82, so that each insulation strip 64 is approximately thesame length as each staple strip 82. The strips 64 may also containpre-molded or extruded guides that may assist in aligning the stripswithin the staple clip, such as by providing transverse ridges that mayalign with the transverse grooves or partitions existing betweenadjacent staples 80 along strip 82.

In another embodiment, insulated staples may not be prefabricated priorto being inserted into any device 10, and instead, staples 80, 82 andinsulation 62, 64 may be independently loaded into the stapler 10. Inthis instance, the staples 80, 82 and insulation 62, 64 may subsequentlybecome engaged or associated with each other before, during, or afterstaple discharge. In this embodiment, the insulation may be supplied asa strip, as coiled or an in-line strip, or any other known manner.

Staples 80, which may be included within staple strip 82, may be formedof metal, plastic, or any composite material. As mentioned above,staples 80 and strips 82 may be specifically designed for a device 10,or may comprise any commercially available staple or staple strip. Inone embodiment, staple 80 comprises a continuous member having a bight84 and a pair of legs 86 extending there from. Staple 80 does not haveto be formed from a single continuous member, and may instead beassembled from multiple members, which is also true for insulation form62. The transition between bight 84 and each leg 86 generally forms acorner 88 that may be radiused. This radius may be relatively small,such as, for example, 1/32 of an inch, to deter any buckling of anassociated leg 86. It is contemplated that staples 80 may comprise anysize and shape. For example, staple lengths may comprise, withoutlimitation, lengths of ¼″ (inch), ⅝″, ½″, or 9/16″, while staple widthsmay comprise 0.4″ to 0.67″. The staple material may comprise anycross-sectional size, and, in one embodiment, comprises material that is0.075″ wide and 0.035″ thick. Generally, for any given staple, thegreater the staple material cross-section and/or the deeper the stapleis to be driven, more power that a device 10 must provide to achieve thedesired drive depth. In one embodiment, device 10 drives a staple thatis 0.670″ and 9/16″ long, and formed of 0.075″ wide and 0.035″ thickmaterial.

Staples 80 also include a tip 88 for engaging and penetrating a targetwork piece. This tip 88 may form an arrow-like tip, where biased edgesextend from opposing sides of the staple and converge centrally alongthe thickness of leg 86 to form a central point as shown in FIG. 19. Itis also contemplated that staple may be a divergent point staple, inwhich the point of the tip 88 is formed along a different side edge ofeach leg 86, as opposed to being formed centrally. It is contemplatedthat each tip 88 may have a different point type, and that one tip maybe asymmetric with regard to the other tip 88, or maybe opposite of orotherwise different than the other tip 88.

Staple strips 82 generally contain a plurality of staples 80. Generallystaples 80 may be assembled in a substantially abutting relation andjoined by an adhesive, but other means may be used. Heat may also beapplied to cure or set the adhesive, and pressure may be applied tocondense and align the plurality of staples into strip form. Further,staples, whether in individual or strip form, may be coated with a gripcompound, which improves a discharged staple's ability to resist aremoval force—a force that attempts to remove the staple from the mediuminto which it has been discharged. Examples of possible grip compoundsinclude any commercially known or used compounds or adhesives. Inoperation, the adhesive properties may be activated while the staple isbeing driven into the target work piece, as penetration may causefriction, which in turn generates heat to activate the adhesive orbonding properties.

It has been disclosed that, in one embodiment, the driving force isprovided by a solenoid 12. Solenoids are advantageous since they arecapable of providing higher driving forces while also being capable ofquickly firing and returning to a ready position. Further, solenoids areelectrically operated. These advantages are desirous in heavy dutyindustrial applications, especially since electronic devices may becomeportable with the use of batteries. However, solenoids require increasedelectrical power to generate higher drive forces. And when desiring toalso provide a portable device, a DC source, such as a battery, maygenerally be used. This provides difficulty since the size of a batteryis limited when being used for a portable, hand-held device.Consequently, the limit in size also limits the battery's storagecapacity. This ultimately affects and controls the degree of power thatmay be provided over an extended duration, because the battery should becapable of providing enough power and charge life to adequately generatethe elevated drive forces in the solenoid for a minimum amount of chargecycles. Otherwise, the portable hand-held device is not desirous to auser.

A capacitor 100 is generally used to supply the requisite energy to thesolenoid 12 in a DC powered device. In one embodiment, the capacitor isa high voltage capacitor. The supplied energy is used to charge thecoil, which in turn magnetically drives an armature 14, and, thereby,drives a pushrod 16 for fastener discharge. When it is desirous toquickly and repeatedly fire the solenoid, such as within 1.5-3 seconds,the capacitor must also quickly and repeatedly charge and discharge.This provides a problem, as capacitors generate heat when they arecharged and discharged. This problem is exacerbated when repeatedlycharging and discharging (a “charging cycle”) a capacitor, but even moreso when the charging cycle occurs are higher or increasing rates. Ifusing ordinary high voltage capacitors to operate at approximately 20second charging cycles, the capacitors will rapidly fail afterapproximately a few hundred charging cycles due to the heat. The use ofultra-capacitors or super-capacitors may generally provide adequateenergy storage capabilities, as each provides high volume storage;however, ultra and super caps are limited to significantly slower chargeand discharge rates. Therefore, it is desirous to use a capacitor thatis both capable of storing an adequate amount of energy, and quickly andrepeatedly charging and discharging while generating lower amounts ofheat.

In one embodiment, a flash or photoflash high voltage capacitor 100 isused to provide stored energy to solenoid 12. A flash capacitor iscapable of quickly charging and discharging, and storing elevatedamounts of energy for heavy duty applications, while generating lessheat due to lower internal resistance. Flash capacitors are also betterable to withstand higher heat. However, photoflash capacitors aregenerally used in photography flash applications, where the flashcapacitor provides energy to a flash tube having near zero impedance(internal resistance). In this application, the flash capacitor 100 willbe used to provide energy to a solenoid having relatively highimpedance, as the solenoid tends to resist any movement from itspre-firing (ready) position. In one embodiment, a flash capacitor havingat least 1,000 microfarad (uF) is used. Flash capacitors that may beused may provide well over 1400 uF. In these embodiments, flashcapacitor 100 may have a charging capacity of at least 180 volts;however, in one embodiment, the voltage is approximately between 330 and390 volts. In another embodiment, a 360 working volt (390 peak volt),1200 uF flash capacitor is used. All capacitance values may beapproximately 10% higher to account for manufacturing tolerances. For aflash capacitor operating at approximately 1200 uF and 360 volts, theflash capacitor provides upwards of approximately 78 Joules of energy(energy equals 0.5×(capacitance×voltage squared). However, it iscontemplated that device 10 may be used in lighter duty applications,and therefore, the capacitor may operate at levels below thoseidentified above. For example, in lighter duty uses, it is contemplatedthat a 330 volt flash capacitor having 400-800 uF of capacitance isused. Regardless of the capacitor being used, it is contemplated that alight duty application may be charge a capacitor to 180 volts or less,as each any capacitor may be charged below a full charge. It iscontemplated that capacitors having lower or higher voltages and/orcapacitance may be used, as the applications and operating conditionsfor device 10 may vary. In particular embodiments, to a more durabledevice 10 having a longer life expectancy, flash capacitor 100 may be ahigh temperature capacitor, which has a temperature rating between85-110 degrees Celsius, although it is contemplated that highertemperature rated capacitors may be used. It is contemplated that lowertemperature rated capacitors may be used, especially in lighter dutyapplications. For a capacitor rated at 110 degrees Celsius, device 10may be capable of performing on average approximately 100,000 firingcycles performed continuously at approximately 19 second intervals.Therefore, a flash capacitor 100 may be successfully used in thisheavier duty application to repeatedly fire the solenoid 12 at quickercycle times over longer periods of time.

A heat sink 102, as shown in FIG. 15, may be used in conjunction withflash capacitor 100 to further reduce the heat of the capacitor, andtherefore increase solenoid 12 firing cycle time. Even though flashcapacitor 100 provides improved charging and discharging rates whilegenerating significantly less heat, heat is still generated. Therefore,a heat sink 102 may be used to conduct heat from capacitor 100, therebyallowing capacitor 100 to generate more heat that would otherwise bedetrimental to the performance and durability of capacitor 100. Heatsink 102 may include heat dissipating protrusions 103 and may be madefrom any heat conducting material, such as, without limitation,aluminum.

Control circuit 110 is generally provided in device 10, such as on acircuit board, to communicate electricity between battery 104, capacitor100, and solenoid 12 and to perform various functions with regard todevice 10. To take advantage of and improve upon the capabilities andadvantages provided by solenoid 12 and capacitor 100, circuitry 110 mayinclude features that improve the charging and discharging rate ofcapacitor 100, and the repeated firing of solenoid 12. Other featuresmay be included within circuitry 110 that improve the operation ofdevice 10. An embodiment of control circuit 110 is shown in FIGS. 26A-D.The functions and results of control circuit 110 are described herein inaccordance with exemplary embodiments of the present invention, and inno way limits the inventors to these exemplary embodiments, as it isunderstood that alternative methods and circuitries, whether hard orsoft logic, may exist to accomplish the spirit of the present invention.

In one embodiment, control circuit 110 includes a high voltagegeneration circuit 120. This circuit 120 converts the DC voltageprovided by battery 104 to a higher voltage for charging high voltagecapacitor 100, which may be a flash capacitor. Accordingly, circuit 120includes a transformer 122. Circuit 120 also controls the charging ofcapacitor 100, and consequently may include related circuitry or logicto increase the charging rate of flash capacitor 100, and to reduce theenergy loss within circuit 120. Such circuitry is represented generally,in an exemplary embodiment, by charge controller 124. The high voltagegeneration circuit 120 quickly charges a high voltage capacitor 100,which in turn quickly releases stored energy to drive solenoid 12. Inthis exemplary embodiment, charge controller 124 comprises an LT® 3750controller, which is a proprietary product of Linear Technology (“LT”)and is believed to be protected at least in part by U.S. Pat. Nos.6,518,733, 6,636,021, and 7,292,005, the disclosure of each such patent,in its entirety, is hereby incorporated by reference. In thisembodiment, high voltage generation circuit 120 is capable of fullycharging a 360 volt, 1200 uF flash capacitor between 2 and 3 seconds, orcharging the same capacitor to 180 volts within approximately 1.5seconds. The quick firing and recharging allows for frequent use by auser. In another embodiment, controller 124 may be a flyback converter,which is used to rapidly charge larger capacitors, such as flashcapacitor 100. It is contemplated that other capacitor chargingcircuits, as well as high current capacitive charging circuits, may beused in device 10 to control the charging of capacitor 100, and toachieve increased charging rates.

It is contemplated that it may be desirable to vary the driving power ofsolenoid 12, such as when desiring to drive fasteners into harder orsofter materials. To achieve this, a variable power control 132 may beused, which may be operated manually by a dial 106, to vary the chargeof capacitor 100. In one embodiment, the variable power control is apotentiometer, which may vary the voltage within voltage control circuit130. It is contemplated that other means of adjusting power, known toone having ordinary skill in the art, such as, for example, a variableresistor, may be used. In one exemplary embodiment, as shown in voltagecontrol circuit 130, a power switch may be included with potentiometer132 for turning device 10 on and off. In this embodiment, a signalgenerated by potentiometer 132, such as, for example, a change involtage, may be recognized by microcontroller 140. If microcontroller140 identifies an increase in voltage from potentiometer 132, a signalis sent to high voltage generation circuit 120 to increase the charge ofcapacitor 100 accordingly (increased charge of capacitor 100 relates toan increase in solenoid 12 drive power). This signal may be a stepfunction, which may be filtered by R6 and C7 and adjusted by R7 asnecessary. If the microcontroller 140 identifies a drop in voltage, asignal is sent to a bleeder 150 to lower the voltage level in capacitor100, if the stored energy is above the desired amount. It iscontemplated that an insulated gate bipolar transistor (IGBT) may beused instead of an SCR (silicon controlled rectifier) (T2) or thyristor112 to cause current to flow from capacitor 100, as the IGBT can controlpower output by limiting or interrupting the discharge of capacitor 100,which would terminate the supply of current or charge to solenoid 12.This would allow for a quicker recharge of capacitor 100 since capacitor100 is not entirely drained. In one embodiment, a monostablemultivibrator, such as Motorola's MC14538 (a dual precision,retriggerable, resettable, monostable multivibrator) may provide aspecific period of time for an IGBT to remain open. It is contemplatedthat other methods may be used to vary and control the power of device10.

In other embodiments, as shown in FIGS. 25 and 25A, solenoid 12 powermay be varied by using a hardness sensor 109 a. Sensor 109 a may engagea target work piece. In one embodiment, a pin 109 b engages the workpiece. Pin 109 b attempt to penetrate the target material, and thereforewill be displaced more with harder materials as the pin does notpenetrate the material as easily. For example, pin 109 b will move ordeflect more in response to harder materials, while pin 109 b willdeflect less with softer materials, as pin 109 b will tend to penetratethe softer materials and better maintain its initial position.Therefore, when a particular fastener drive depth is to be maintained,if pin 109 b indicates that the material is harder, more power will beprovided to solenoid 12, such as by increasing the charge on capacitor100. To the contrary, if pin 109 b indicates that the material issofter, then the charge in capacitor will be less, which may requirebleeding of power if the power is above what is recommended by thesensor 109. A potentiometer or variable resistor 109 c, or any othermeans of varying power contemplated above, may provide a signal, such asa change in voltage, which corresponds to the deflection of a hardnesspin 109 b as it engages a target work piece. It is contemplated that thehardness reading may be reported to a user, or may be used toautomatically adjust the power supplied to solenoid 12 as discussed andcontemplated in other power varying embodiments above. This sensor 109 awould allow the device 10, such as by way of microcontroller 140, toadjust the power according to the hardness of the work piece material.

In another embodiment, a depth sensor 107 may used determine the heightof the object that is to be secured by way of a discharged fastener, andadjust the power accordingly to control the drive depth of the fastener.The power may be adjusted by a potentiometer or any other means ofvarying power contemplated above, and may be used by device 10 to adjustthe power of device 10 as contemplated and described above, with regardto the other sensors. If a target object is thicker (or taller), then afastener will not be able to be driven as deep into the work piece sincethe target object will impede the fasteners path. More importantly, asuser may not want to risk driving the fastener into the target object,as the object may become damaged. Accordingly, the depth sensor 107 willultimately generate a signal to direct device 10 to charge capacitor 100to a lower power level, thereby driving the fastener to a shallowerdepth. Conversely, if a target object is small, the more a particularfastener can be driven into a work piece without damaging the targetobject. The safety blade 56 discussed above could function, or operate,as this variable power sensor, although stand-alone sensing mechanismsmay be used.

SCR gate drive circuit 160 fires solenoid 12 after receivingauthorization from firing safety circuit 170. In operation, drivecircuit 160 closes the normally open SCR gate (T2), which causes a rushof current from capacitor 100 through solenoid 12, and the ultimatefiring of device 10. Once the current decreases below a particularvalue, such as 0.5 amps, the SCR is reset to an open position.Subsequently, capacitor 100 may be recharged as directed by high voltagegeneration circuit 120. SCR gate drive circuit 160 also provides asafety feature that prevents radio frequency (RF) signals frominadvertently closing SCR gate (T2) 112 by closing high speed switchingtransistors Q5 and Q3, which are susceptible to RF energy. When RFtransmitters, such as walkie-talkies and cell phones, generate a localhigh RF energy field, high speed capacitance bypass capacitors C17, C18divert the RF energy so that a charge does not develop acrosstransistors Q3 and Q5. Such a charge could close the transistors (highspeed switches), which would ultimately close the SCR gate and causecapacitor 100 to inadvertently discharge.

Backup capacitor (C4) 101 is included to provide protection against anyfailure or disconnection of flash capacitor 100. In one embodiment,backup capacitor 101 may have a substantially smaller capacity than, orbe of a sufficiently small size with respect to, flash capacitor 100. Inan exemplary embodiment, capacitor 101 is a 600 volt, 0.1 microfaradcapacitor. Nevertheless, backup capacitor 101 is sufficient to ensureproper operation of the high voltage generation circuit 120, even thoughit may take a few charge cycles to reach the programmed output voltage.Basically backup capacitor 101 keeps the output voltage under control inthe presence of a failure or disconnection or capacitor 100.

In one embodiment, the charge of capacitor 100 may be maintained to aprogrammed (target) voltage, while the tool awaits firing in a readymode. This process may be referred to as a “pickling” process.Initially, the high voltage generation circuit 120 first chargescapacitor 100 to a programmed voltage. In one exemplary embodiment, thecapacitor 100 is charged to between 320 and 360 volts. Once reaching theprogrammed voltage, the generation circuit 120 is turned off. If thiscircuit does not automatically maintain the voltage on 100, the voltageon capacitor 100 will slowly discharge. To complicate matters more, thehigher the programmed voltage, such as in this application, the morerapid the discharge. For instance, capacitor 100 may lose one to twovolts per second following completion of the initial charge when set toits maximum voltage value. Therefore, in one embodiment, after thestaple gun reaches a ready state (ready to fire) and the charging ofcapacitor 100 is terminated, the pickling process charges capacitor 100periodically to maintain the charge on capacitor 100. In one embodiment,the microcontroller 140 will turn off the charge controller 124 and waita period of time, such as, for example, 400 milliseconds, before turningthe charge controller 124 on to re-charge capacitor 100. Once it isdetermined that capacitor is fully charged, the microcontroller 140again turns off the charge controller 124 to terminate charging ofcapacitor 100. The pickling cycle then repeats as desired to maintainthe charge of capacitor 100 while in ready mode until the device 10 isfired or until reaching a sleep state timeout or detection of acritically low battery. Although any interval may be used, in oneexemplary embodiment, the cycle occurs every 400 milliseconds. Thepickling process may be achieved or controlled by means other thenexplained in the embodiment above.

A firing safety circuit 170 may be provided to control the firing of,and prevent the misfiring of, device 10. In one embodiment, triggerswitch 172 and safety switch 174 must both be closed, meaning that auser must both pull the trigger 55 b and displace the safety blade 56before the microcontroller can begin its firing sequence. In anotherembodiment, the safety blade 56 must be engaged (thereby closing thesafety switch) before engaging the trigger 55 b. In particularembodiment, after a fastener has been fired, the trigger 55 b and safety56 must be released (i.e., the respective switches 172, 174 opened) andre-engaged before firing the next fastener. This may help prevent anyunintentional fastener firing.

Once the firing sequence is begun, there are two additional featuresthat may prevent device 10 from firing. First, the proper executionfiring sequence instructions are verified. If the instructions are notperformed correctly, the microprocessor sends a false signal to a dualD-type flip-flop circuit 176. In one embodiment, the firing sequenceincludes instructions to clear a watchdog clock. These instructions areplaced at different locations within the firing sequence. If the clockis not cleared within a predetermined time limit, meaning that theinstructions to clear the clock have not been properly executed, a falsesignal is sent to the flip-flop circuit 176 to prevent firing of device10. It is contemplated that other techniques may be used to verify thatperformance of the firing sequence occurs properly. The second safetyfeature that may also be overcome, in this embodiment, is that thetrigger and safety switches 172, 174 do not open after the firingsequence has begun. In this embodiment, this is accomplished by hardlogic via flip-flop circuit 176 . If one of the trigger or safety switch172, 174 opens, the corresponding pull down resistor R19, R18 cannot beovercome, and therefore the corresponding overriding clear pins on U5Aand U5B (pins 1, 13) pull the logic to low and a false signal (logiclow) is sent to AND gate U4. Because U4 will not allow the SCR (T2) 112to open without receiving true signals from both U5A and U5B, the SCR112 will not open and solenoid 12 will not fire. Although othersolutions may be possible, this firing safety circuit is valuable as itis a low cost solution for providing these safety features.

Processor logic power supply circuit 180 regulates the voltage withincircuitry 110 with an ultra-low quiescent current low dropout regulatorU6. A field effect transistor Q8 reduces the current load in circuit 110when the microcontroller is in hibernation by powering off the controlcircuit in the high voltage generation circuit 120 and other resistors,such as the battery monitoring resistors.

A power control circuit 190 controls the supply of power to high voltagegeneration circuit 120. It also protects batteries from over-discharge.Lithium ion batteries, as well as other rechargeable batteries, mustgenerally retain a minimum voltage to prevent failure, which results inthe inability of a battery to be recharged. If it is determined that abattery's voltage falls below a critical power fail subpoint voltage,microcontroller 140 turns NPN transistor Q4 off, which turns off MOSFETQ2 and ultimately the current to high voltage generation circuit 120.This prevents any further draw from the battery in an attempt to preventbattery failure.

Power control circuit 190 may also provides a soft start capability.When microcontroller 140 turns on, MOSFET Q2 also turns on. Because Q2may have low impedance, a high jump in current would normally occur,which could result in a surge within high voltage generation circuit120. This surge could cause capacitor 100 to fire solenoid 12, ifcapacitor had a residual charge. To avoid this, C11, R2, and R3 providea soft start capability by providing a linear ramp of current to highvoltage generation circuit 120.

Although microcontroller 140 generally controls the firing of solenoid12, it also provides other background operations, such as measuring andmonitoring the battery voltage and temperature. If a dangerously lowbattery voltage occurs, device 10 may automatically shutdown to preventbattery cell damage. Device 10 may also shutdown when the battery celldischarge rate or temperature exceeds know limits. Sensors also existthat may indicate a capacitor over temperature condition, or overvoltage conditions. Microcontroller 140 may also may control thebleeding of charge from capacitor 100, if desired. Microcontroller mayalso control and operate a laser guide LED, a work light LED, and theLED that indicates when the device 10 is ready for fastener discharge,if the capacitor is still charging, or if there is an issue or errorwithin the battery or circuitry that needs attention. For example, afast flashing light of one color may indicate that the battery ischarging, and when colored light stops flashing, the battery is chargedto the desired level. If there are fast-flashing alternating colors, itmay indicate a low-battery condition. If the alternating flashing ofcolors slows, it may indicate that battery is ready for firing but onlya limited number of discharges remain within the battery's capacity,such as, for example, 40 shots remain.

In one embodiment, the power source 104 is a DC power source, which maybe a rechargeable battery, such as, for example, a 12-18 volt NiMH(nickel metal hydride), NiCd (nickel cadmium), or a Lithium-ion (Li-ion)battery. Nevertheless, it is contemplated that any commerciallyavailable battery, whether or not rechargeable, may be used. In aneffort to reduce the weight of the device 10, a 12 volt (V) or 14.4Vbattery 104 may be used over an 18 volt battery without a significanteffect on the overall performance of the device 10. In anotherembodiment, a 16.8 Li-ion battery is used. In one embodiment, the 1.5-3second charge and discharge cycle times identified earlier in theapplication may be achieved with as low as a 14.4V battery. In oneembodiment, Li-ion batteries are used as they provide more powerdensity, and therefore, provide more shots per charge. This also allowsthe weight of device 10 to be reduced, since fewer Li-ions batteries maybe used—as Li-ion batteries are more efficient. For example, in oneembodiment, when using four 4.2V Li-ions cells (14.4V total), 1.55 amphours are provided, which results in approximately 580 shots per charge.When using a 12-cell 14.4V Ni-Cad battery pack, approximately 970 shotsmay be achieved per charge. However, the 12-cell Ni-Cad battery weightsapproximately 2.35 pounds, while the 4-cell Li-ion battery weighs 0.77pounds.

The battery 104 attaches to the rear side of the device 10 in a mannerthat allows for its removal. Locating the battery 104 in the rear sidehelps to balance the device 10 and to better facilitate single handoperation of the device 10. In one embodiment, battery 104 must beremoved prior to disassembling device 10. Further, capacitor 100 mayautomatically be bled upon removal of battery 104. Finally, it iscontemplated that the device 10 may also be powered solely, or inaddition to a DC power source, by an alternating current (AC) powersource. The AC power source may be used as an alternative to the DCsource 104, and/or to charge battery 104.

It is contemplated that one or more LEDs could be used to indicate thatthe capacitor 100 is charging, the stapler 10 is ready to fire, thebattery 104 is low or empty, and/or the tool has a fault condition. Itis also contemplated that an LED or other light source may be includedon the stapler 10 to light any work surfaces. Laser guides may also beused to mark the firing locations, such as to indicate the center of thetool or the side boundaries of the fastening area. A flip-up studcentering guide may also exist to ensure the cable or the like is alwaysis secured to the center of a 2×4 or 2×6 stud.

While this invention has been described with reference to particularembodiments thereof, it shall be understood that such description is byway of illustration and not by way of limitation. Accordingly, the scopeand content of the invention are to be defined only by the terms of theappended claims.

1. A nailer or stapler device comprising: a solenoid; a fastener strikerin operational communication with the solenoid; a capacitor inoperational communication with the solenoid; and, a control circuit inoperational communication with the capacitor, wherein the controlcircuit includes a firing safety circuit, the safety circuit having ahard logic override that prevents the stapler from discharging a staplewhen either the trigger switch and/or the safety switch is opened aftera capacitor firing sequence operation has been initiated, wherein thecapacitor firing sequence operation is initiated after both a triggerswitch and a safety switch are closed.
 2. The device recited in claim 1,wherein control circuit includes a watchdog timer that is cleared by theexecution of particular instructions, and wherein the firing sequence isterminated if the watchdog timer is not cleared within a particularperiod of time according to a particular sequence of instructions. 3.The device recited in claim 1, wherein the control circuit includes aSCR gate drive circuit, the drive circuit including a capacitor thatredirects a charge provided by radiofrequency or electromagnetictransmissions that would otherwise accumulate to close a transistor, thetransistor configured to facilitate the opening of a capacitor dischargegate.
 4. The device recited in claim 1, wherein the control circuitincludes a power control circuit that provides a gradual increase inpower to a high voltage generation circuit for charging the capacitor,the increase in power occurring when the device is turned on or awakensfrom a hibernation state.
 5. The device recited in claim 1, the devicefurther comprising: a hardness sensor configured to engage a work pieceand generate a signal corresponding to the hardness of the work piecefor use by the control circuit to vary the charging limit of thecapacitor between a minimum and maximum charge.
 6. The device recited inclaim 1, the device further comprising: a depth sensor arranged alongthe device to determine the depth to which a fastener discharged into awork piece based upon a height of a target object, the target objectbeing located on the work piece and positioned between the work pieceand the device, the depth sensor generating a signal corresponding tothe height of the target object for use by the control circuit to varythe discharge power by varying the charging limit of the capacitorbetween a minimum and maximum charge.
 7. The device recited in claim 1,wherein the fastener striker having a length extending in a fastenerdriving direction and a pair of opposing sides separated by a thicknessof the striker, the striker further including a gusset forming aridge-like protrusion extending outwardly along a length of the strikerfrom one of the striker sides, the gusset being positioned within awidth of the striker side between the terminal edges of the side.
 8. Amethod of discharging a fastener from a nailer or stapler device, themethod comprising: providing a fastener-discharging device having asolenoid, a capacitor, and a control circuit; charging the capacitor;engaging a safety mechanism to close a safety switch of the controlcircuit; engaging a trigger to close a trigger switch of the controlcircuit; initiating a capacitor firing sequence operation afterdetermining the safety switch and the trigger switch are closed afterperforming the steps of engaging a safety mechanism and engaging atrigger; and, maintaining the safety switch and the trigger switch in aclosed position to prevent operation of a hard logic override, the hardlogic override configured to terminate the firing sequence after thefiring sequence was initiated according to the prior step to preventdischarge of the capacitor if one or more of the safety switch and thetrigger switch are opened before the firing sequence operation iscompleted; and, discharging the capacitor to operate a solenoid when thefiring sequence operation is completed, the solenoid thereby driving astriker to discharge a fastener.
 9. The method as recited in claim 8,further comprising the following step: diverting, by way of a capacitor,a charge provided by radiofrequency or electromagnetic transmissionsthat otherwise would accumulate to close a transistor that facilitatesthe opening of a capacitor discharge gate to discharge the flashcapacitor and fire the solenoid.
 10. The method as recited in claim 8,further comprising the following step: gradually ramping-up power whenthe device is turned on or when the device awakens from a hibernationstate to help prevent a surge of power in the circuit.
 11. The method asrecited in claim 8, further comprising the following step: engaging awork piece with the fastener-discharging device, the device including ahardness sensor for measuring the hardness of a work piece; generating asignal by way of the hardness sensor, where the signal is related to thedeflection of the sensor; adjusting the power output of the deviceaccording to the signal, wherein the output power increases when thedeflection increases, and the output power decreases when the deflectiondecreases.
 12. The method as recited in claim 8, further comprising thefollowing step: engaging a work piece with the fastener-dischargingdevice, the device having a depth sensor configured to generate a signalrepresenting a height of a target object located between the device andthe work piece, the device configured to discharge a fastener comprisinga staple having a pair of legs and a bight section extending between thepair of legs; generating a signal by way of the depth sensor, the signalrepresenting the height of the target object; determining an amount ofoutput power for discharging the staple a particular depth into the workpiece such that the bight section of the staple is generally maintaineda distance from the work piece generally corresponding to the height ofthe target work piece; discharging the flash capacitor to drive thesolenoid at the output power determined according to the prior stepwherein the output power generally increases as the target object heightdecreases and the output power generally decreases as the heightincreases.